tessl/maven-org-springframework-boot--spring-boot-starter-tomcat

Starter for using Tomcat as the embedded servlet container, providing default servlet container functionality for Spring Boot web applications

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Auto-Configuration

Name: tessl/maven-org-springframework-boot--spring-boot-starter-tomcat
Author: tessl

Automatic configuration classes that set up Tomcat components based on classpath detection and application properties. Spring Boot's auto-configuration system provides convention-over-configuration setup while allowing extensive customization through properties and custom beans.

Capabilities

ServletWebServerFactoryAutoConfiguration

Main auto-configuration class for servlet web servers, including Tomcat support. Conditionally creates web server factory beans and customizers.

/**
 * Auto-configuration for servlet web server factories
 */
@AutoConfiguration
@ConditionalOnClass(ServletRequest.class)
@ConditionalOnWebApplication(type = WebApplicationType.SERVLET)
@EnableConfigurationProperties(ServerProperties.class)
@Import({ ServletWebServerFactoryAutoConfiguration.BeanPostProcessorsRegistrar.class,
         ServletWebServerFactoryConfiguration.EmbeddedTomcat.class,
         ServletWebServerFactoryConfiguration.EmbeddedJetty.class,
         ServletWebServerFactoryConfiguration.EmbeddedUndertow.class })
public class ServletWebServerFactoryAutoConfiguration {
    
    /** Creates servlet web server factory customizer */
    @Bean
    public ServletWebServerFactoryCustomizer servletWebServerFactoryCustomizer(
            ServerProperties serverProperties, 
            ObjectProvider<WebListenerRegistrar> webListenerRegistrars,
            ObjectProvider<CookieSameSiteSupplier> cookieSameSiteSuppliers);
    
    /** Creates Tomcat servlet web server factory customizer */
    @Bean
    @ConditionalOnClass(name = "org.apache.catalina.startup.Tomcat")
    public TomcatServletWebServerFactoryCustomizer tomcatServletWebServerFactoryCustomizer(
            ServerProperties serverProperties);
    
    /** Creates forwarded header filter when configured */
    @Bean
    @ConditionalOnMissingBean
    @ConditionalOnProperty(value = "server.forward-headers-strategy", havingValue = "framework")
    public FilterRegistrationBean<ForwardedHeaderFilter> forwardedHeaderFilter();
}

ServletWebServerFactoryConfiguration.EmbeddedTomcat

Configuration class specifically for embedded Tomcat web server factory creation.

/**
 * Configuration for embedded Tomcat servlet web server factory
 */
@Configuration(proxyBeanMethods = false)
@ConditionalOnClass({ Servlet.class, Tomcat.class, UpgradeProtocol.class })
@ConditionalOnMissingBean(value = ServletWebServerFactory.class, 
                          search = SearchStrategy.CURRENT)
static class EmbeddedTomcat {
    
    /** Creates Tomcat servlet web server factory bean */
    @Bean
    TomcatServletWebServerFactory tomcatServletWebServerFactory(
            ObjectProvider<TomcatConnectorCustomizer> connectorCustomizers,
            ObjectProvider<TomcatContextCustomizer> contextCustomizers,
            ObjectProvider<TomcatProtocolHandlerCustomizer<?>> protocolHandlerCustomizers) {
        
        TomcatServletWebServerFactory factory = new TomcatServletWebServerFactory();
        
        // Apply all discovered customizers
        factory.getTomcatConnectorCustomizers()
               .addAll(connectorCustomizers.orderedStream().collect(Collectors.toList()));
        factory.getTomcatContextCustomizers()
               .addAll(contextCustomizers.orderedStream().collect(Collectors.toList()));
        factory.getTomcatProtocolHandlerCustomizers()
               .addAll(protocolHandlerCustomizers.orderedStream().collect(Collectors.toList()));
        
        return factory;
    }
}

TomcatServletWebServerFactoryCustomizer

Applies ServerProperties configuration to Tomcat servlet web server factories.

/**
 * Customizer that applies ServerProperties to Tomcat servlet web server factories
 */
public class TomcatServletWebServerFactoryCustomizer
        implements WebServerFactoryCustomizer<TomcatServletWebServerFactory>, Ordered {
    
    /** Constructor with server properties */
    public TomcatServletWebServerFactoryCustomizer(ServerProperties serverProperties);
    
    /** Applies Tomcat-specific configuration from properties */
    @Override
    public void customize(TomcatServletWebServerFactory factory) {
        ServerProperties.Tomcat tomcatProperties = serverProperties.getTomcat();
        
        // Apply TLD skip patterns
        if (!tomcatProperties.getAdditionalTldSkipPatterns().isEmpty()) {
            factory.addTldSkipPatterns(tomcatProperties.getAdditionalTldSkipPatterns()
                                      .toArray(new String[0]));
        }
        
        // Apply context root redirect setting
        if (tomcatProperties.getRedirectContextRoot() != null) {
            customizeRedirectContextRoot(factory, tomcatProperties.getRedirectContextRoot());
        }
        
        // Apply relative redirects setting
        customizeUseRelativeRedirects(factory, tomcatProperties.getUseRelativeRedirects());
        
        // Apply MBean registry setting
        customizeDisableMBeanRegistry(factory, tomcatProperties.getMbeanregistry());
    }
    
    /** Returns execution order for this customizer */
    @Override
    public int getOrder();
}

TomcatWebServerFactoryCustomizer

Applies common Tomcat configuration for both servlet and reactive web server factories.

/**
 * Customizer that applies common Tomcat configuration to web server factories
 */
public class TomcatWebServerFactoryCustomizer
        implements WebServerFactoryCustomizer<ConfigurableTomcatWebServerFactory>, Ordered {
    
    /** Constructor with server properties */
    public TomcatWebServerFactoryCustomizer(ServerProperties serverProperties);
    
    /** Applies common Tomcat configuration from properties */
    @Override
    public void customize(ConfigurableTomcatWebServerFactory factory) {
        ServerProperties.Tomcat tomcatProperties = serverProperties.getTomcat();
        
        // Base directory configuration
        if (tomcatProperties.getBasedir() != null) {
            factory.setBaseDirectory(tomcatProperties.getBasedir());
        }
        
        // Background processor delay
        if (tomcatProperties.getBackgroundProcessorDelay() != null) {
            factory.setBackgroundProcessorDelay(
                (int) tomcatProperties.getBackgroundProcessorDelay().getSeconds());
        }
        
        // URI encoding
        if (tomcatProperties.getUriEncoding() != null) {
            factory.setUriEncoding(tomcatProperties.getUriEncoding());
        }
        
        // Apply connector customizations
        customizeConnector(factory, tomcatProperties);
        
        // Apply static resource settings
        customizeStaticResources(factory, tomcatProperties.getResource());
        
        // Apply remote IP configuration
        customizeRemoteIpValve(factory, tomcatProperties.getRemoteip());
    }
    
    /** Returns execution order for this customizer */
    @Override
    public int getOrder();
}

ReactiveWebServerFactoryAutoConfiguration

Auto-configuration for reactive web servers, including Tomcat reactive support.

/**
 * Auto-configuration for reactive web server factories
 */
@AutoConfiguration
@ConditionalOnClass(HttpHandler.class)
@ConditionalOnWebApplication(type = WebApplicationType.REACTIVE)
@EnableConfigurationProperties(ServerProperties.class)
@Import({ ReactiveWebServerFactoryAutoConfiguration.BeanPostProcessorsRegistrar.class,
         ReactiveWebServerFactoryConfiguration.EmbeddedTomcat.class,
         ReactiveWebServerFactoryConfiguration.EmbeddedJetty.class,
         ReactiveWebServerFactoryConfiguration.EmbeddedUndertow.class,
         ReactiveWebServerFactoryConfiguration.EmbeddedNetty.class })
public class ReactiveWebServerFactoryAutoConfiguration {
    
    /** Creates reactive web server factory customizer */
    @Bean
    public ReactiveWebServerFactoryCustomizer reactiveWebServerFactoryCustomizer(
            ServerProperties serverProperties);
}

ReactiveWebServerFactoryConfiguration.EmbeddedTomcat

Configuration class for embedded Tomcat reactive web server factory.

/**
 * Configuration for embedded Tomcat reactive web server factory  
 */
@Configuration(proxyBeanMethods = false)
@ConditionalOnClass({ Tomcat.class })
@ConditionalOnMissingBean(value = ReactiveWebServerFactory.class,
                          search = SearchStrategy.CURRENT)
static class EmbeddedTomcat {
    
    /** Creates Tomcat reactive web server factory bean */
    @Bean
    TomcatReactiveWebServerFactory tomcatReactiveWebServerFactory(
            ObjectProvider<TomcatConnectorCustomizer> connectorCustomizers,
            ObjectProvider<TomcatContextCustomizer> contextCustomizers,
            ObjectProvider<TomcatProtocolHandlerCustomizer<?>> protocolHandlerCustomizers) {
        
        TomcatReactiveWebServerFactory factory = new TomcatReactiveWebServerFactory();
        
        // Apply customizers
        factory.getTomcatConnectorCustomizers()
               .addAll(connectorCustomizers.orderedStream().collect(Collectors.toList()));
        factory.getTomcatContextCustomizers()
               .addAll(contextCustomizers.orderedStream().collect(Collectors.toList()));
        factory.getTomcatProtocolHandlerCustomizers()
               .addAll(protocolHandlerCustomizers.orderedStream().collect(Collectors.toList()));
        
        return factory;
    }
}

TomcatReactiveWebServerFactoryCustomizer

Applies configuration to Tomcat reactive web server factories.

/**
 * Customizer for Tomcat reactive web server factories
 */
public class TomcatReactiveWebServerFactoryCustomizer
        implements WebServerFactoryCustomizer<TomcatReactiveWebServerFactory>, Ordered {
    
    /** Constructor with server properties */
    public TomcatReactiveWebServerFactoryCustomizer(ServerProperties serverProperties);
    
    /** Applies Tomcat reactive-specific configuration */
    @Override
    public void customize(TomcatReactiveWebServerFactory factory);
    
    /** Returns execution order for this customizer */
    @Override
    public int getOrder();
}

WebSocket Auto-Configuration

TomcatWebSocketServletWebServerCustomizer

Customizes Tomcat for WebSocket support in servlet environments.

/**
 * Customizer for Tomcat WebSocket support in servlet environments
 */
@Configuration(proxyBeanMethods = false)
@ConditionalOnClass({ Tomcat.class, WsSci.class })
static class TomcatWebSocketConfiguration {
    
    /** Creates WebSocket servlet web server customizer */
    @Bean
    @ConditionalOnMissingBean(name = "tomcatWebSocketServletWebServerCustomizer")
    TomcatWebSocketServletWebServerCustomizer tomcatWebSocketServletWebServerCustomizer() {
        return new TomcatWebSocketServletWebServerCustomizer();
    }
}

TomcatWebSocketReactiveWebServerCustomizer

Customizes Tomcat for WebSocket support in reactive environments.

/**
 * Customizer for Tomcat WebSocket support in reactive environments
 */
@Configuration(proxyBeanMethods = false)
@ConditionalOnClass({ Tomcat.class, WsSci.class })
static class TomcatWebSocketReactiveConfiguration {
    
    /** Creates WebSocket reactive web server customizer */
    @Bean
    @ConditionalOnMissingBean(name = "tomcatWebSocketReactiveWebServerCustomizer")
    TomcatWebSocketReactiveWebServerCustomizer tomcatWebSocketReactiveWebServerCustomizer() {
        return new TomcatWebSocketReactiveWebServerCustomizer();
    }
}

Metrics Auto-Configuration

TomcatMetricsAutoConfiguration

Auto-configuration for Tomcat metrics collection through Micrometer.

/**
 * Auto-configuration for Tomcat metrics collection
 */
@AutoConfiguration(after = { MetricsAutoConfiguration.class,
                           CompositeMeterRegistryAutoConfiguration.class })
@ConditionalOnClass({ Tomcat.class, MeterRegistry.class })
@ConditionalOnBean(MeterRegistry.class)
@ConditionalOnProperty(value = "management.metrics.web.server.request.autotime.enabled",
                      matchIfMissing = true)
@EnableConfigurationProperties(MetricsProperties.class)
public class TomcatMetricsAutoConfiguration {
    
    /** Creates Tomcat metrics binder */
    @Bean
    @ConditionalOnMissingBean
    public TomcatMetricsBinder tomcatMetricsBinder(MeterRegistry meterRegistry) {
        return new TomcatMetricsBinder(meterRegistry);
    }
    
    /** Creates Tomcat metrics web server factory customizer */
    @Bean
    @ConditionalOnMissingBean
    public TomcatMetricsWebServerFactoryCustomizer tomcatMetricsCustomizer(
            MeterRegistry meterRegistry, MetricsProperties metricsProperties) {
        return new TomcatMetricsWebServerFactoryCustomizer(meterRegistry, metricsProperties);
    }
}

Conditional Configuration

Auto-configuration uses Spring Boot's conditional annotations to ensure proper component setup:

Class Presence Conditions

@ConditionalOnClass({ Servlet.class, Tomcat.class, UpgradeProtocol.class })
// Only activate when Tomcat classes are available

@ConditionalOnClass(name = "org.apache.catalina.startup.Tomcat")  
// Check for specific Tomcat class by name

Bean Existence Conditions

@ConditionalOnMissingBean(value = ServletWebServerFactory.class)
// Only create if no other web server factory exists

@ConditionalOnBean(MeterRegistry.class)
// Only create if MeterRegistry bean exists

Property Conditions

@ConditionalOnProperty(value = "server.forward-headers-strategy", 
                      havingValue = "framework")
// Only activate when specific property value is set

@ConditionalOnProperty(value = "management.metrics.web.server.request.autotime.enabled",
                      matchIfMissing = true)
// Activate by default unless explicitly disabled

Web Application Type Conditions

@ConditionalOnWebApplication(type = WebApplicationType.SERVLET)
// Only for servlet web applications

@ConditionalOnWebApplication(type = WebApplicationType.REACTIVE)  
// Only for reactive web applications

Configuration Processing Order

Auto-configuration components are processed in a specific order:

Core Auto-Configuration: ServletWebServerFactoryAutoConfiguration or ReactiveWebServerFactoryAutoConfiguration
Factory Creation: Tomcat web server factory beans are created
Built-in Customizers: Framework-provided customizers are applied
Property Customizers: Properties-based customizers apply configuration
User Customizers: Application-defined customizer beans are discovered and applied
Final Validation: Configuration is validated and server is prepared for startup

This ordering ensures that user customizations can override framework defaults while maintaining proper initialization sequence.

Install with Tessl CLI

npx tessl i tessl/maven-org-springframework-boot--spring-boot-starter-tomcat

docs

auto-configuration.md

configuration-properties.md

index.md

server-customization.md

web-server-factories.md

tile.json

tessl/maven-org-springframework-boot--spring-boot-starter-tomcat